Online Code Editor

I am looking for something that I can edit the code of a page online.
I want something like Notepad++ but in the browser. I preferably want something with similar features of Notepad++ like tag highlighting, colored code. Stuff like that. Does someone know of anything like that?
It also needs to be able to to the code highlighting on CSS, HTML, PHP

I know I'm going to get someone to say "Just Google It" but i am not sure what to Google. I'm not coming up with anything.